Roundness Estimation of Sedimentary Rocks Using Eliptic Fourier and Deep Neural Networks

Sedimentary rocks analysis is useful in geological science, economic sector, and risk evaluation. Roundness is a morphological parameter that provide information to characterize and classify sedimentary material. Roundness degrees is estimated from the contour of the particle. Waddell (1932) proposed a remarkable method based on the measurement of particle’s curvature. This method is accurate; evertheless, it is not invariant to scale and rotation. This problem can be solved by mapping the contour to the frequencydomain, however, spectral analysis is a difficult task. Based on these two approaches, we propose to use a deep neural network whose input is the elliptical Fourier spectrum and target is roundness proposed by Wadell. The training database consists of 623 realrocks images from some geological phenomena. We have found the neural networks perform very well on the 88.8% of rocks

Quantitative textural analysis of sedimentary grains and basin subsidence modelling

Part 1: Quantitative textural analysis Shape analysis can provide important information regarding the origin, transport and deposition history of grains. Particle shape measurement has been an active area of research for sedimentologists since the 20th century. However, there is a lack of standardised methodology for quantitative characterisation of grain shapes. The main objective of this work is to develop methodologies that can be used by sedimentologists for quantitative textural analysis of grains such that the results obtained are comparable. A modular suite of code written in the Mathematica environment for the quantitative characterisation of sedimentary grains in 2- dimensions is presented. This image analysis package can be used to analyse consolidated as well as loose sediment samples. Using newly implemented image analysis methods, 20 loose sediment samples from four known depositional environments (beach, aeolian, glacial and fluvial) were analysed. This research aims to identify the most useful shape parameters for textural characterisation of populations of grains and determine the relative importance of the parameters. A key aspect of this study is to determine whether, in a particular sedimentary environment, textural maturity of the samples can be ranked based on their grain shape data. Furthermore, discrimination of sedimentary depositional environments is explored on the basis of grain shape. The available shape parameters suffer from a common shortcoming that particles, which are visually distinct, are not differentiated. To address this issue, the Inverse Radius of Curvature (IRC) plot which can be used to identify corners and measure their sharpness is introduced. Using the IRC plot, four shape parameters are proposed: number of corners, cumulative angularity, sharpest corner and straight fraction. This methodology is applied to a 4000 sand grain dataset. The textural analysis software package developed here allow users to quantitatively characterise large set of grains with a fast, cheap and robust methodology. This study indicate that textural maturity is readily categorised using automated grain shape parameter analysis. However, it is not possible to absolutely discriminate between different depositional environments on the basis of shape parameters alone. The four new shape parameters proposed here based on the IRC plot can be collectively used to quantitatively describe grains shape which correlates closely with visual perceptions. This work opens up the possibility of using detailed quantitative textural dataset of sediment grains along with other standard analyses (mineralogy, bulk composition, isotopic analysis, etc) for diverse sedimentary studies. Part 2: Basin modelling Subsidence modelling is an important part of basin analysis to better understand the tectonic evolution of sedimentary basins. The McKenzie model has been widely applied for subsidence modelling and stretching factor estimation for sedimentary basins formed in an extensional tectonic environment. In this contribution, a numerical model is presented that takes into account the effect of sedimentary cover on stretching factor estimation. Subsidence modelling requires values of physical parameters (crustal thickness, lithospheric thickness, stretching factor, etc.) which may not be always available. With a given subsidence history of a basin estimated using a stratigraphic backstripping method, these parameters can be estimated by quantitatively comparing the known subsidence curve with modelled subsidence curves. In this contribution, a method to compare known and modelled subsidence curves is presented aiming to constrain valid combinations of stretching factor, crustal thickness and lithospheric thickness of a basin. The parameter fitting method presented here is first applied to synthetically generated subsidence curves. Next, a case study using a known subsidence curve from the Campos Basin, offshore Brazil is considered. The range of stretching factors estimated for the Campos basin from this study is in accordance with previous work, with an additional estimate of corresponding lithospheric thickness. This study provides insights into the dependence of subsidence modelling methods on assumptions about input parameters as well as allowing for the estimation of valid combinations of physical lithospheric parameters, where the subsidence history is known

The transfer and persistence of environmental trace indicators, and methods for digital data acquisition from photographs and micrographs: applications for forensic science research

Environmental forms of trace evidence (such as mineral grains, pollen grains, algae, and sediment) can offer valuable insights within forensic casework. An issue facing forensic science as a whole, and these environmental indicators specifically, is a relative dearth of empirical research which would underpin the interpretation of such indicators when attempting forensic reconstruction. This thesis aims to address this lacuna, undertaking experiments to: (1) Explore variables which affect the rates of transfer and persistence, with specific focus upon quartz grains (a terrestrial indicator) and diatom valves (an aquatic indicator) upon footwear materials (a substrate that has been under-represented in past studies); (2) Conduct research into the effects of particle size and morphology upon transfer and persistence; (3) Develop and adapt methodologies to undertake this research. Accordingly, the outputs of this thesis are: (1) The creation of new datasets which could inform the interpretation of these trace indicators within forensic investigations and crime reconstruction scenarios and (2) The development of novel methodologies which could be employed in future research to attempt to accelerate data collection and analysis, without compromising on accuracy. This research is interdisciplinary, combining theory from forensic science, analytical techniques from the environmental sciences, and some elements of image processing and analysis. This research was funded by the Engineering and Physical Sciences Research Council of the United Kingdom through the Security Science Doctoral Training Research Centre (UCL SECReT) based at University College London (EP/G037264/1)

Microfluidic assembly of zein microcapsules

Microencapsulation has been widely used for many applications to stabilize functional materials and to control the release of them. With the rapid changes in consumer needs, there are increased and diversified demands for microencapsulation technology in the food industry; for instance, flavor masking, nutrient protection, and probiotics delivery. The controlled release property of core materials from the microcapsules is one of the key factors to achieve the essential goal of incorporating microcapsules in foods. Despite the extensive research on microencapsulation in the past, it is still a challenge for the industry to customize delivery systems to meet the diverse demands, especially when the materials to be used are limited to food-grade materials. In addition, the widely used top-down processes such as high-pressure homogenization and microfluidization cannot provide sufficient control on the properties of microcapsules. Those energy-intensive processes also generate substantial shear and heat, which have negative impacts on vitamins, proteins, and bioactives in microcapsules. Hence, there is a critical need to develop a mild bottom-up process that enables accurate controls over the process and the properties of the microcapsules. Microfluidics drew a great interest as a mean to synthesize or fabricate microcapsules. It features many advantages such as highly homogeneous and tunable product properties and non-invasive process, and makes handling of delicate materials feasible. To date, the majority of materials used in microfluidic process are non-food grade synthetic polymers. In order to apply this technology in the food industry, it is necessary to find suitable food-grade materials. Zein is a water-insoluble protein that has shown a potential as a building block of delivery carriers for functional ingredients and is a good candidate to be used in microfluidic process. Therefore, the overall goal of this study is to develop a methodology to assemble zein microcapsules using microfluidic approach. First, zein nanoparticles were used as building blocks to stabilize emulsions. By tuning the wettability of the zein nanoparticles with sodium caseinate, the emulsion stability was further improved. An optimal zein: caseinate ratio of 10:3 increased the interfacial coverage of oil droplets. This emulsifying ability of zein was improved by tuned wettability, which could be used as a food ingredient. Then, shifting from the conventional process, a microfluidic process was introduced to fabricate hollow zein microcapsules with tunable permeability. The generation of zein microcapsules was driven by self-assembly of zein at the oil-water interface followed by internal phase separation. By controlling the concentration of zein in dispersing phase and the flow rates of continuous and dispersing phases during microfluidic process, the rate of release was accurately adjusted. At the same time, the internal structure of the microcapsules was controlled from single core to multiple cores as well as the particle size of microcapsules. Based on the established microfluidic process, the zein microcapsules were further fabricated to modify mechanical properties and degree of wrinkling. These two properties are critical engineering properties of microcapsules to function properly for many applications. The incorporation of phytic acid significantly changed the plasticity and increased the degree of wrinkling of zein microcapsules, which were confirmed by nanoindentation and image analysis. Finally, an antimicrobial peptide nisin was encapsulated as an example to demonstrate an application of this technology. Nisin is a natural antimicrobial agent that can inhibit the growth of Listeria monocytogenes. However, the application of nisin has the limitation due to its instability in food matrices. Our study showed that the encapsulation of nisin in zein using a microfluidic process was able to control the release of nisin and significantly improved its antimicrobial activity against Listeria monocytogenes in fresh cheese. The efficacy of nisin was also extended from three days with non-encapsulated nisin to more than one week with the encapsulated nisin

Smėlio dalelių morfologinių parametrų įtakos grunto mechaninėms savybėms eksperimentiniai ir skaitiniai tyrimai

Disertacijoje nagrinėjama smėlinių gruntų elgsena tiesiogiai įvertinant morfologinius dalelių parametrus. Pagrindiniai tyrimai susideda iš trijų etapų: morfologinių parametrų tyrimai vaizdų analizės programa ir skanuojančiu elektroniniu mikroskopu; eksperimentiniai grunto spūdumo ir tiesioginio kirpimo bandymai; skaitiniai modeliuojamo grunto bandymai ir rezultatų gretinimas. Pagrindinis disertacijos tikslas – ištirti morfologinių parametrų įtaką grunto mechaninėms savybėms bei sudaryti modeliuojamo grunto diskretinį ir matematinius modelius. Įgyvendinant pagrindinį tikslą sukurti grunto spūdumo ir tiesioginio kirpimo metodikų patobulinimai. Darbe sprendžiami du pagrindiniai uždaviniai: eksperimentinių ir skaitinių bandymų rezultatų palyginimas bei spūdumo rezultatų priklausomybės nuo morfologinių grunto dalelių parametrų analizė. Pirmasis uždavinys su-formuluotas, atsižvelgiant į palyginti mažą tokių tyrimų skaičių. Antrasis siejasi su grunto diskretiniu modeliu, skaitiniu modeliavimu diskrečiųjų e-lementų metodu įvertinant deformuojamo grunto spūdumo elgseną. Disertaciją sudaro įvadas, trys skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatomos disertacijos tema autoriaus paskelbtos publikacijos ir pranešimai konferencijose bei disertacijos struktūra. Pirmasis skyrius skirtas tirtų gruntų inžinerinių geologinių sąlygų, eksperimentinių ir skaitinių tyrimų apžvalgai. Jame pateikta literatūros analizė ir dalis eksperimentinių duomenų. Skyriaus pabaigoje formuluojamos išvados ir tikslinami disertacijos uždaviniai. Antrajame skyriuje pateikta atliktų eksperimentinių ir skaitinių bandymų apžvalga apie grunto morfologinių parametrų nustatymą, tirtų gruntų spūdumo ir kerpamojo stiprio savybes bei skaitinio modeliavimo rezultatai. Skyriaus pabaigoje formuluojamos išvados ir tikslinami disertacijos uždaviniai. Trečiajame skyriuje pateiktas eksperimentinių ir skaitinių grunto tyrimų rezultatų palyginimas, įvertinantis 1–2 skyriuose pateiktus duomenis. Disertacijos tema paskelbta 19 straipsnių: keturi – straipsnių rinkiniuose, įtrauktuose į Thomson ISI sąrašą, vienas – konferencijų medžiagoje, referuotoje Thomson ISI duomenų bazėje, keturi – kitų tarptautinių duomenų bazių cituojamuose žurnaluose, du – recenzuojamose konferencijų medžiagose. Disertacijos tema perskaityti 8 pranešimai Lietuvos bei kitų šalių konferencijose